Diaminopyrazole compounds and the use thereof in the oxidation dyeing of keratinous fibres

ABSTRACT

The invention relates to novel diaminopyrazole having formula (I), wherein: R 1 , R 2 , identical or different, represent a C 3  C 5  mono- or polyhydroxyalkyl, isopropyl, n-propyl or ethyl group, said groups being linear or branched, and their physiologically acceptable salts. The invention also relates to a composition for dyeing keratinous fibres containing a compound having formula (I) and the method for using same.

[0001] The present invention relates to novel diaminopyrazolederivatives, to a composition for the oxidation dyeing of keratinfibers, and in particular of human keratin fibers such as the hair,comprising at least one diaminopyrazole derivative as oxidation base,and to the oxidation dyeing processes using it.

[0002] It is known practice to dye keratin fibers, and in particularhuman hair, with dye compositions containing oxidation dye precursors,in particular ortho- or para-phenylenediamines, ortho-aminophenols orpara-aminophenols and heterocyclic compounds such as diaminopyrazolederivatives, which are generally referred to as oxidation bases. Theoxidation dye precursors, or oxidation bases, are colorless or weaklycolored compounds which, when combined with oxidizing products, can giverise to colored compounds and dyes by a process of oxidativecondensation.

[0003] It is also known that the shades obtained with these oxidationbases can be varied by combining them with couplers or colorationmodifiers, the latter being chosen in particular from aromaticmeta-diamines, meta-aminophenols, meta-diphenols and certainheterocyclic compounds.

[0004] The variety of molecules used as oxidation bases and couplersmakes it possible to obtain a wide range of colors.

[0005] The so-called “permanent” coloration obtained by means of theseoxidation dyes must moreover satisfy a certain number of requirements.Thus, it must have no toxicological drawbacks and it must allow shadesof the desired strength to be obtained and have good resistance toexternal agents (light, bad weather, washing, permanent-waving,perspiration and friction).

[0006] The dyes must also allow white hairs to be covered, and, lastly,they must be as unselective as possible, i.e. they must allow thesmallest possible differences in coloration to be produced over theentire length of the same keratin fiber, which may indeed be differentlysensitized (i.e. damaged) between its tip and its root. They must alsoshow good chemical stability in the formulations, and must have a goodtoxicological profile.

[0007] Furthermore, for a certain number of applications, dyes thatproduce chromatic shades on the hair are desired.

[0008] Patent application DE 42 34 885 discloses 4,5-diamino-pyrazolederivatives, which, when used together with various couplers, especiallybenzoxazines, give chestnut-brown shades with blue, red, violet,aubergine or coppery glints.

[0009] However, these dyes do not satisfy all the above requirements.

[0010] The Applicant has now discovered, entirely surprisingly andunexpectedly, that it is possible to obtain dyes which are capable ofproducing powerful, particularly chromatic, bright and relativelyunselective colorations, which have excellent properties of resistanceto the various attacking factors to which keratin fibers may besubjected, by using as oxidation base the diaminopyrazoles of theformula (I) below or physiologically acceptable salts thereof.

[0011] One subject of the present invention is thus the noveldiaminopyrazoles having the following general formula (I):

[0012] in which:

[0013] R₁ and R₂, which may be identical or different, denote a ethyl,n-propyl, isopropyl or mono- or polyhydroxy (C₃-C₅)alkyl group, it beingpossible for these groups to be linear or branched.

[0014] A subject of the invention is also the physiologically acceptableacid or base salts of the compounds of formula (I), such as thehydrochlorides, hydrobromides, sulfates, tartrates, lactates oracetates.

[0015] R₁ preferably denotes an ethyl, n-propyl, isopropyl, propyl,butyl or pentyl group which is substituted with one or more OH radicals,it being possible for these groups to be linear or branched.

[0016] R₂ preferably denotes a linear or branched ethyl, n-propyl,isopropyl, ethyl, propyl, butyl or pentyl group, which is substitutedwith one or more OH radicals.

[0017] A subject of the invention is also a composition for theoxidation dyeing of keratin fibers, and in particular of human keratinfibers such as the hair, characterized in that it contains, in a mediumthat is suitable for dyeing, as oxidation base, at least onediaminopyrazole of formula (I) above, or physiologically acceptable acidsalts thereof.

[0018] As mentioned above, the colorations obtained with the oxidationdye composition in accordance with the invention are powerful,particularly bright and chromatic. They in particular produce shadesthat are free of or contain very little blue or yellow. Furthermore,they show excellent properties of resistance with respect to the actionof various external agents (light, bad weather, washing,permanent-waving, perspiration and friction).

[0019] A subject of the invention is also a process for the oxidationdyeing of keratin fibers using such a dye composition.

[0020] As examples of diaminopyrazoles of formula (I) according to theinvention, mention may be made of the following compounds: StructureName Structure Name Structure Name

2,N3-di- ethyl-2H- pyrazole- 3,4-diamine

N3-ethyl- 2-propyl- 2H- pyrazole- 3,4-diamine

N3-ethyl- 2-iso- propyl-2H- pyrazole- 3,4-diamine

2-ethyl- N3-propyl- 2H- pyrazole- 3,4-diamine

2, N3-di- propyl- 2H- pyrazole- 3,4-diamine

2-iso- propyl-N3- propyl-2H- pyrazole- 3,4-diamine

2-ethyl- N3-iso- propyl-2H- pyrazole- 3,4-diamine

N3-iso- propyl-2- propyl-2H- pyrazole- 3,4-diamine

2,N3-diiso- propyl-2H- pyrazole- 3,4-diamine

2-(4-amino- 2-ethyl- 2H-pyrazol- 3-ylamino)- ethanol

3-(4-amino- 2-propyl- 2H-pyrazol- 3-ylamino)- propan-1-ol

3-(4-amino- 2-(3- hydroxy- propyl)- 2H-pyrazol- 3-ylamino)- propan-1-ol

3-(4-amino- 5-ethyl- aminopyra- zol-1-yl)- propan-1-ol

3-(4-amino- 5-propyl- aminopyra- zol-1-yl)- propan-1-ol

3-[4-amino- 2-(2- hydroxy- propyl)-2H- pyrazol-3- ylamino])- propan-1-ol

1-(4-amino- 2-ethyl-2H- pyrazol-3- ylamino)- propan-2-ol

1-(4-amino- 2-(2- hydroxy- propyl)-2H- pyrazol-3- ylamino])- propan-2-ol

1-(4-amino- 2-isobutyl- 2H-pyrazol- 3-ylamino)- propan-2-ol

1-(4-amino- 5-ethyl- amino- pyrazol-1- yl)propan- 2-ol

4-[4-amino- 2-(2- hydroxy- butyl)-2H- pyrazol-3- ylamino])- butan-1-ol

4-(4-amino- 2-iso- propyl-2H- pyrazol-3- ylamino)- 3-methyl- butan-1-ol

1-[4-amino- 5-(2- hydroxy- ethylamino) pyrazol-1- yl]propan- 2-ol

1-(4-amino- 5-isopro- pylamino- pyrazol-1- yl)propan- 2-ol

3-(4-amino- 5-ethyl- amino- pyrazol-1- yl)propane- 1,2-diol

3-(4-amino- 5-isopro- pylamino- pyrazol-1- yl)propane- 1,2-diol

3-[4-amino 5-(2-hy- droxyethyl- amino)- pyrazol-1- yl]-propane- 1,2-diol

3-[4-amino- 5-(2- hydroxypro- pylamino)- pyrazol-1- yl]propane- 1,2-diol

3-[4-amino- 5-(2,3-di- hydroxypro- pylamino)- pyrazol-1- yl]propane-1,2-diol

4-[4-amino- 5-(2,3-di- hydroxypro- pylamino)- pyrazol-1- yl]butane-2- ol

4-(4-amino- 5-ethyl- amino- pyrazol-1- yl)butan- 2-ol

4-(4-amino- 5-isopro- pylamino- pyrazol-1- yl)butan- 2-ol

4-(4-amino- 2-ethyl-2H- pyrazol-3- ylamio)- butan-2-ol

4-(4-amino- 2-propyl- 2H-pyrazol- 3-ylamino)- butan-2-ol

4-[4-amino- 2-(3- hydroxy- butyl)-2H- pyrazol- 3-ylamino]- butan-2-ol

4-[4-amino- 2-(3- hydroxy- butyl)-2H- pyrazol-3- ylamino]- butan-2-ol

1-(4-amino- 5-ethyl- aminopyra- zol-1-yl)- butan-2-ol

1-(4-amino- 5-isopro- pylamino- pyrazol-1- yl)butan- 2-ol

1-(4-amino- 2-ethyl-2H- pyrazol-3- ylamino)- butan-2-ol

1-(4-amino- 2-propyl- 2H-pyrazol- 3-ylamino)- butan-2-ol

1-[4-amino- 5-(2-hy- droxybutyl- amino)- pyrazol-1- yl]butan- 2-ol

1-(4-amino- 5-ethyl- amino- pyrazol-1- yl)butan- 2-ol

4-[4-amino- 5-(2-hy- droxybutyl- amino)- pyrazol-1- yl]butane- 1,2-diol

1-(4-amino- 5-isopro- pylamino- pyrazol-1- yl)butan- 2-ol

4-[4-amino- 5-(3,4-di- hydroxybut- ylamino)- pyrazol-1- yl]butane-1,2-diol

4-(4-amino- 2-propyl- 2H-pyrazol- 3-ylamino)- butane-1,2- diol

4-(4-amino- 2-iso- propyl-2H- pyrazol-3- ylamino)- butane-1,2- diol

4-[4-amino- 2-(3- hydroxy- butyl)-2H- pyrazol-3- ylamino]- butane-1,2-diol

4-(4-amino- 5-propyl- aminopyra- zol-1-yl)- butane-1,2- diol

4-(4-amino- 5-isopro- pylamino- pyrazol-1- yl)butane- 1,2-diol

1-(4-amino- 2-ethyl-2H- pyrazol-3- ylamino)- butane-2,3- diol

1-(4-amino- 2-propyl- 2H-pyrazol- 3-ylamino)- butane-2,3- diol

1-[4-amino- 5-(2,3-di- hydroxybut- ylamino)- pyrazol-1- yl]butane-2,3-diol

1-(4-amino- 5-ethyl- aminopyra- zol-1-yl)- butane-2,3- diol

4-(4-amino- 5-propyl- aminopyra- zol-1-yl)- butane-1,2- diol

4-(4-amino- 5-isopro- pylamino- pyrazol-1- yl)butane- 1,2-diol

4-(4-amino- 2-ethyl-2H- pyrazol-3- ylamino)- butane- 1,2,3-triol

4-[4-amino- 5-(2,3,4- trihydroxy- butyl- amino)pyra- zol-1-yl]- butane-1,2,3-triol

4-(4-amino- 2-iso- propyl-2H- pyrazol-3- ylamino)- butane- # 1,2,3-triol

4-[4-amino- 2-(3-hy- droxy-2- methyl- propyl)-2H- pyrazol-3- ylamino]-butane- 1,2,3-triol

4-(4-amino- 5-ethyl- aminopyra- zol-1-yl)- butane- 1,2,3-triol

4-(4-amino- 5-isopro- pylamino- pyrazol-1- yl)butane- # 1,2,3-triol

3-[4-amino- 2-(3- hydroxy-2- methylpro- pyl)-2H- pyrazol-3- ylamino]-2-methyl- propan-1-ol

2-[4-amino- 5-(3- hydroxy-2- methylpro- pylamino)- pyrazol-1- ylmethyl]-propane- 1,3-diol

3-[4-amino- 2-(3- # hydroxy-2- methylpro- pyl)-2H- pyrazol-3-ylamino]-2- methyl- propan-1-ol

3-(4-amino- 5-ethyl- aminopyra- zol-1-yl)- 2-methyl- propan-1-ol

3-(4-amino- 5- propylamino pyrazol-1- yl)-2- methyl- propan-1-ol

3-(4-amino- 5-iso- propylamino pyrazol-1- yl)-2- methyl- propan-1-ol

2-[4-amino- 5-(3-hy- droxy-2,2- dimethyl- propyl- amino)pyra- zol-1-yl-methyl]- propane- 1,3-diol

3-(4-amino- 2-propyl- 2H-pyrazol- 3-ylamino)- 2,2-di- methyl-propan-1-ol

3-(4-amino- 2-iso- propyl-2H- # pyrazol-3- ylamino)- 2,2-di- methyl-propan-1-ol

3-(4-amino- 5-ethyl- aminopyra- zol-1-yl)- 2,2-di- methyl- propan-1-ol

3-[4-amino- 5-(3-hy- droxy-2,2- dimethyl- propyl- amino(pyra- zol-1-yl]-2,2-di- methyl- propan-1-ol

3-(4-amino- 5-isopro- pylamino- # pyrazol-1- yl)-2,2-di- methyl-propan-1-ol

3-(4-amino- 2-ethyl-2H- pyrazol-3- ylamino)- 2,2-di- methyl- propan-1-ol

2-[(4- amino-2- propyl-2H- pyrazol-3- ylamino)- methyl)- propane-1,3-diol

2-{[4- amino-2-(3- hydroxy- 2,2-di- methylpro- pyl)-2H- # pyrazol-3-ylamino]- methyl}- proane-1,3- diol

5-(4-amino- 2-ethyl-2H- pyrazol-3- ylamino)- pentan-1-ol

5-(4-amino- 2-propyl- 2H-pyrazol- 3-ylamino)- pentan-1-ol

5-(4-amino- 2-isopro- pyl-2H- pyrazol-3- ylamino)- pentan-1-ol

5-(4-amino- 5-ethyl- aminopyra- zol-1-yl)- pentan-1-ol

5-[4-amino- 2-(4- hydroxy- pentyl)-2H- pyrazol-3- ylamino]- pentan-1-ol

5-[4-amino- 5-(5- hydroxypen- tylamino)- pyrazol-1- yl]pentan- 1-ol

1-(4-amino- 2-ethyl-2H- pyrazol-3- ylamino]-3- methyl- butan-2-ol

1-[4-amino- 5-(2-hy- droxy-3- methylbut- ylamino)- pyrazol-1- yl]-3-methyl- butan-2-ol

1-(4-amino- 2-isopro- pyl-2H- pyrazol-3- ylamino)-3- # methyl-butan-2-ol

1-[4-amino- 5-(2- hydroxy-3- methylbut- ylamino)- pyrazol-1- yl]-pentan-2-ol

1-(4-amino- 5-ethyl- amino- pyrazol-1- yl)-3- methyl- butan-2-ol

1-(4-amino- 5-propyl- amino- pyrazol-1- yl)-3- methyl- # butan-2-ol

1-[4-amino- 5-(2-hy- droxy- pentyl- amino)- pyrazol-1- yl]pentan- 2-ol

1-(4-amino- 2-propyl- 2H-pyrazol- 3-ylamino)- pentan-2-ol

1-(4-amino- 2-iso- propyl-2H- pyrazol-3- ylamino)- pentan-2-ol

1-(4-amino- 5-ethyl- amino- pyrazol-1- yl)pentan- 2-ol

1-(4-amino- 5-propyl- amino- pyrazol-1- yl)pentan- 2-ol

5-[4-amino- 5-(3-hy- droxypen- tylamino)- pyrazol-1- yl]- pentane-1,2-diol

5-(4-amino- 2-ethyl-2H- pyrazol-3- ylamino)- pentane- 1,3-diol

5-(4-amino- 2-iso- propyl-2H- pyrazol-3- ylamino)- pentane- 1,3-diol

5-[4-amino- 5-(3,5-di- hydroxypen- tylamino)- pyrazol-1- yl]pentane-1,2,3-triol

5-(4-amino- 5-ethyl- aminopyra- zol-1-yl)- pentane- 1,3-diol

5-[4-amino- 5-(3,5-di- hydroxypen- tylamino)- pyrazol-1- yl]pentane-1,3-diol

5-(4-amino- 5-ethyl- amino- pyrazol-1- yl)pentane- 1,3-diol

5-[4-amino- 2-(3-hy- droxy-2- methyl- butyl)-2H- pyrazol-3- ylamino]-pentane- 1,2,3-triol

5-(4-amino- 2-propyl- 2H-pyrazol- 3-ylamino)- pentane- 1,2,3-triol

5-(4-amino- 2-isopro- pyl-2H- pyrazol-3- ylamino)- # pentane-1,2,3-triol

5-(4-amino- 5-ethyl- amino- pyrazol-1- yl)pentane- 1,2,3-triol

5-[4-amino- 5-(3,4,5- trihydroxy- pentyl- amino)- pyrazol-1- yl]pentane-1,2,3-triol

5-(4-amino- 5-ethyl- amino- pyrazol-1- yl)pentane- 1,2,3-triol

5(4-amino- 2-ethyl-2H- pyrazol-3- ylamino)- pentane- 1,2,3,4- tetraol

5-(4-amino- 2-propyl- 2H-pyrazol- 3-ylamino)- pentane- 1,2,3,4- tetraol

5-(4-amino- 2-isopro- pyl-2H- pyrazol-3- ylamino)- pentane- 1,2,3,4- #tetraol

5-(4-amino- 5-ethyl- amino- pyrazol-1- yl)pentane- 1,2,3,4- tetraol

5-[4-amino- 5-(2,3,4,5- tetra- hydroxy- pentyl- amino)- pyrazol-1-yl]pentane- 1,2,3,4- tetraol

5-[4-amino- 2-(2-hy- droxymeth- ylbutyl)- # 2H-pyrazol- 3-ylamino]-pentane- 1,2,3,4- tetraol

[0021] Among the diaminopyrazoles of formula (I), preference is given tothe following compounds: Structure Name

2,N3-di- ethyl-2H- pyrazole- 3,4-diamine

2-methyl-N3- isopropyl- 2H- pyrazole- 3,4-diamine

1-(4-amino- 2-(2- hydroxy- propyl)-2H- pyrazol-3- ylamino])- propan-2-ol

1-[4-amino- 5-(2- hydroxy- ethylamino) pyrazol-1- yl]propan- 2-ol

3-(4-amino- 5-isopro- pylamino- pyrazol-1- yl)propane- 1,2-diol

3-[4-amino- 5-(2,3-di- hydroxypro- pylamino)- pyrazol-1- yl]propane-1,2-diol

4-(4-amino- 2-iso- propyl-2H- pyrazol-3- ylamino)- butane- 1,2,3-triol

N3-ethyl-2- propyl-2H- pyrazole- 3,4-diamine

2-(4-amino- 2-ethyl-2H- pyrazol-3- ylamino)- ethanol

1-(4-amino- 2-isobutyl- 2H-pyrazol- 3-ylamino)- propan-2-ol

1-(4-amino- 5-isopro- pylamino- pyrazol-1- yl)propan- 2-ol

3-[4-amino 5-(2-hy- droxyethyl- amino)- pyrazol-1- yl]-propane- 1,2-diol

4-(4-amino- 2-ethyl-2H- pyrazol-3- ylamino)- butane- 1,2,3-triol

4-(4-amino- 5-ethyl- aminopyra- zol-1-yl)- butane- 1,2,3-triol

N3-ethyl- 2-iso- propyl-2H- pyrazole- 3,4-diamine

1-(4-amino- 2-ethyl-2H- pyrazol-3- ylamino)- propan-2-ol

1-(4-amino- 5-ethyl- amino- pyrazol-1- yl)propan- 2-ol

3-(4-amino- 5-ethyl- amino- pyrazol-1- yl)propane- 1,2-diol

3-[4-amino- 5-(2- hydroxypro- pylamino)- pyrazol-1- yl]propane- 1,2-diol

4-[4-amino- 5-(2,3,4- trihydroxy- butyl- amino)pyra- zol-1-yl]- butane-1,2,3-triol

4-(4-amino- 5-isopro- pylamino- pyrazol-1- yl)butane- 1,2,3-triol

[0022] The diaminopyrazoles of formula (I) that are more particularlypreferred according to the invention are

[0023] 2,N3-diethyl-2H-pyrazole-3,4-diamine

[0024] 1-(4-amino-2-ethyl-2H-pyrazol-3-ylamino)propan-2-ol

[0025] N3-ethyl-2-isopropyl-2H-pyrazole-3,4-diamine

[0026] 2-ethyl-N3-isopropyl-2H-pyrazole-3,4-diamine

[0027] 2-(4-amino-2-ethyl-2H-pyrazol-3-ylamino)ethanol

[0028] 1-(4-amino-2-ethyl-2H-pyrazol-3-ylamino)propan-2-ol

[0029] 1-[4-amino-2-(2-hydroxypropyl)-2H-pyrazol-3-yl-amino]propan-2-ol

[0030] 1-(4-amino-5-ethylaminopyrazol-1-yl)propan-2-ol

[0031] 3-(4-amino-5-ethylaminopyrazol-1-yl)propane-1,2-diol or theaddition physiologically acceptable acid salts thereof.

[0032] The diaminopyrazoles of formula (I) according to the inventionare prepared, for example, according to the following generalpreparation method:

[0033] The synthetic approach shown below is described in the literatureup to intermediate (2) (J. H. P. Juffermanns, C. L Habraken; J. Org.Chem., 1986, 51, 4656; Klebe et al., Synthesis, 1973, 294; R. Huttel, F.Buchele; Chem. Ber., 1955, 88, 1586). The alkylation and the aminationto obtain the compounds of the type (5) of formula (I) according to theinvention are mentioned, for example, in document DE 42 34 885.

[0034] The dye composition according to the invention especiallycontains from 0.001% to 10% by weight, preferably from 0.05% to 6% byweight and even more preferably from 0.1% to 3% by weight of at leastone substituted N3-diaminopyrazole of formula (I) or salts thereof.

[0035] The dye composition in accordance with the invention may alsocontain, in addition to the diaminopyrazole(s) defined above, at leastone additional oxidation base that may be chosen from the oxidationbases conventionally used in oxidation dyeing and among which mentionmay be made especially of para-phenylenediamines,bis(phenyl)alkylenediamines, para-aminophenols, ortho-aminophenols andheterocyclic bases other than the 4,5-diaminopyrazole used in accordancewith the invention.

[0036] Among the para-phenylenediamines that may be mentioned moreparticularly, for example, are para-phenylenediamine,para-tolylenediamine, 2,6-dimethyl-para-phenylenediamine,2-β-hydroxyethyl-para-phenylene-diamine,2-n-propyl-para-phenylenediamine, 2-isopropyl-para-phenylenediamine,N-(β-hydroxypropyl)-para-phenylenediamine,N,N-bis(β-hydroxyethyl)-para-phenylenediamine,4-amino-N-(β-methoxyethyl)aniline and the para-phenylenediaminesdescribed in French patent application FR 2 630 438, and the additionsalts thereof.

[0037] Among the bis(phenyl)alkylenediamines that may be mentioned moreparticularly, for example, areN,N′-bis-(β-hydroxyethyl)-N,N′-bis(4′-aminophenyl)-1,3-diamino-propanol,N,N′-bis(β-hydroxyethyl)-N,N′-bis(4′-amino-phenyl)ethylenediamine,N,N′-bis(4-aminophenyl)tetra-methylenediamine,N,N′-bis(β-hydroxyethyl)-N,N′-bis(4-aminophenyl)tetramethylenediamine,N,N′-bis(4-methyl-aminophenyl)tetramethylenediamine andN,N′-bis(ethyl)-N,N′-bis(4′-amino-3′-methylphenyl)ethylenediamine, andthe addition salts thereof.

[0038] Among the para-aminophenols that may be mentioned moreparticularly, for example, are para-aminophenol, 4-amino-3-methylphenol,4-amino-3-fluorophenol, 4-amino-3-hydroxymethylphenol,4-amino-2-methylphenol, 4-amino-2-hydroxymethylphenol,4-amino-2-methoxymethylphenol, 4-amino-2-aminomethylphenol and4-amino-2-(β-hydroxy-ethylaminomethyl)phenol, and the addition saltsthereof.

[0039] Among the ortho-aminophenols that may be mentioned moreparticularly, for example, are 2-aminophenol, 2-amino-5-methylphenol,2-amino-6-methylphenol and 5-acetamido-2-aminophenol, and the additionsalts thereof.

[0040] Among the heterocyclic bases that may be mentioned moreparticularly, for example, are pyridine derivatives, pyrimidinederivatives, pyrazole derivatives other than the diaminopyrazoles offormula (I) used in accordance with the invention, and the additionsalts thereof.

[0041] When they are used, these additional oxidation bases preferablyrepresent from 0.0005% to 12% by weight relative to the total weight ofthe dye composition and even more preferably from 0.005% to 6% by weightrelative this weight.

[0042] The oxidation dye compositions in accordance with the inventionmay also contain at least one coupler and/or at least one direct dye,especially to modify the shades or to enrich them with glints.

[0043] The couplers that may be used in the oxidation dye compositionsin accordance with the invention may be chosen from the couplersconventionally used in oxidation dyeing, and among which mention may bemade especially of meta-phenylenediamines, meta-amino-phenols,meta-diphenols, mono- or polyhydroxylated naphthalene derivatives andheterocyclic couplers such as, for example, indole or pyridinederivatives, and the addition salts thereof.

[0044] By way of examples, mention may be made of2-methyl-5-aminophenol, 5-N-(β-hydroxyethyl)amino-2-methyl-phenol,6-chloro-2-methyl-5-aminophenol, 3-aminophenol, 1,3-dihydroxybenzene,1,3-dihydroxy-2-methylbenzene, 4-chloro-1,3-dihydroxybenzene,2,4-diamino-1-(β-hydroxy-ethyloxy)benzene,2-amino-4-(β-hydroxyethylamino)-1-methoxybenzene, 1,3-diaminobenzene,1,3-bis(2,4-di-aminophenoxy)propane, 3-ureidoaniline,3-ureido-1-di-methylaminobenzene, sesamol,1-β-hydroxyethylamino-3,4-methylenedioxybenzene, α-naphthol,2-methyl-1-naphthol, 6-hydroxyindole, 4-hydroxyindole,4-hydroxy-N-methylindole, 2-amino-3-hydroxypyridine,6-hydroxybenzomorpholine, 3,5-diamino-2,6-dimethoxy-pyridine,1-N-(β-hydroxyethyl)amino-3,4-methylene-dioxybenzene and2,6-bis(β-hydroxyethylamino)toluene, and the addition salts thereof.

[0045] When they are present, these couplers especially represent from0.0001% to 10% of the total weight of the dye composition, preferablyfrom 0.005% to 5% by weight and even more preferably from 0.1% to 3% ofthis weight.

[0046] In general, the addition acid salts that may be used in thecontext of the dye compositions of the invention (oxidation bases andcouplers) are chosen especially from the hydrochlorides, hydrobromides,sulfates, tartrates, lactates and acetates.

[0047] The medium that is suitable for dyeing (or support) usedaccording to the invention consists of water or of a mixture of waterand at least one organic solvent chosen from C₁-C₄ lower alkanols,polyols and polyol ethers, aromatic alcohols, similar products andmixtures thereof.

[0048] The dye composition according to the invention may also containvarious adjuvants conventionally used in compositions for dyeing thehair, such as anionic, cationic, nonionic, amphoteric or zwitterionicsurfactants or mixtures thereof, anionic, cationic, nonionic, amphotericor zwitterionic polymers or mixtures thereof, mineral or organicthickeners, antioxidants, reducing agents, sunscreens, penetratingagents, sequestering agents, fragrances, buffers, dispersants,conditioners, for instance silicones, film-forming agents, preservingagents and opacifiers.

[0049] The pH of the dye composition according to the invention isbetween 3 and 12.

[0050] Needless to say, a person skilled in the art will take care toselect this or these optional additional compound(s) such that theadvantageous properties intrinsically associated with the oxidation dyecomposition in accordance with the invention are not, or are notsubstantially, adversely affected by the envisaged addition(s).

[0051] The dye composition according to the invention may be in variousforms, such as in the form of liquids, creams or gels, or in any otherform that is suitable for dyeing keratin fibers, and especially humanhair.

[0052] Another subject of the invention is a process for dyeing keratinfibers, and in particular human keratin fibers such as the hair, usingthe dye composition as defined above.

[0053] According to this process, at least one dye composition asdefined above is applied to the fibers, for a time that is sufficient todevelop the desired coloration, either in air or using an oxidizingagent. The dye composition may optionally contain oxidation catalysts,so as to accelerate the oxidation process.

[0054] According to a first embodiment of the process of the invention,the coloration of the fibers may be performed without adding anoxidizing agent, solely by contact with atmospheric oxygen.

[0055] According to a second embodiment of the process of the invention,at least one dye composition as defined above is applied to the fibers,the color being revealed at acidic, neutral or alkaline pH using anoxidizing agent that is added to the composition just at the time ofuse, or which is present in an oxidizing composition appliedsimultaneously or sequentially in a separate manner.

[0056] According to this second embodiment of the dyeing process of theinvention, the dye composition described above is preferably mixed, atthe time of use, with an oxidizing composition containing, in a mediumthat is suitable for dyeing, at least one oxidizing agent present in anamount that is sufficient to develop a coloration. The mixture obtainedis than applied to the keratin fibers and is left for an action time of3 to 50 minutes and preferably 5 to 30 minutes, after which the fibersare rinsed, washed with shampoo, rinsed again and dried.

[0057] The oxidizing agent present in the oxidizing composition asdefined above may be chosen from the oxidizing agents conventionallyused for the oxidation dyeing of keratin fibers, and among which mentionmay be made of hydrogen peroxide, urea peroxide, alkali metal bromatesand persalts such as perborates and persulfates. Hydrogen peroxide isparticularly preferred.

[0058] The pH of the oxidizing composition containing the oxidizingagent as defined above is such that, after mixing with the dyecomposition, the pH of the resulting composition applied to the keratinfibers preferably ranges between 3 and 12, and even more preferablybetween 5 and 11. It is adjusted to the desired value by means ofacidifying or basifying agents usually used in the dyeing of keratinfibers, and as defined above.

[0059] The oxidizing composition as defined above may also containvarious adjuvants conventionally used in compositions for dyeing thehair and as defined above.

[0060] The composition that is finally applied to the keratin fibers maybe in various forms, such as in the form of liquids, creams or gels, orin any other form that is suitable for dyeing keratin fibers, andespecially human hair.

[0061] Another subject of the invention is a multi-compartment device ordyeing “kit” or any other multi-compartment packaging system, a firstcompartment of which contains the dye composition as defined above, anda second compartment of which contains the oxidizing composition asdefined above. These devices may be equipped with a means for applyingthe desired mixture to the hair, such as the devices described in patentFR-2 586 913 in the name of the Applicant.

[0062] The examples that follow are intended to illustrate the inventionwithout, however, limiting its scope.

EXAMPLES EXAMPLES OF SYNTHESIS

[0063] Synthesis of 3,4,5-tribromopyrazole (1):

[0064] An aqueous solution (350 ml) containing sodium hydroxide (24 g,0.6 mol) and pyrazole (10 g, 0.147 mol) was prepared with stirring.After cooling the reaction medium to 20° C., Br₂ (72 g, 0.45 mol) wasadded dropwise over 1 hour, while maintaining the temperature between20° C. and 25° C. The reaction was monitored by thin layerchromatography (TLC) (50% hexane/50% EtOAc or ethyl acetate). Theprecipitate was filtered off and washed with demineralized water (100ml). The filtrate was acidified to pH 6-7 using HCl (10%, 33 g, 0.27mol) and maintaining the temperature between 20 and 25° C. Theprecipitate thus formed was filtered off and washed with demineralizedwater (100 ml). The combined solids were maintained at reflux inDean-Stark apparatus in the presence of toluene (200 ml). At the end ofcollection of the water, the organic phase was filtered while hot. Thesolvent was evaporated down to a residual volume of 110 ml. The solutionwas cooled to 0-5° C. for 1 hour. The precipitate formed was collectedby filtration, washed with cold toluene (20 ml) and dried under vacuumat 80° C. to give the 3,4,5-tribromopyrazole (1) in the form of anoff-white solid (30 g, 67%).

[0065]¹³C-NMR: (100 MHz, d₆-DMSO): 97.7-116.1-126.4

[0066] Melting point: 182-184° C.

[0067] Synthesis of 3,5-dibromo-4-nitropyrazole (2):

[0068] HNO₃ (d=1.50 g/ml; 18 ml, 0.429 mol) was added dropwise over 10minutes to a solution of 3,4,5-tribromopyrazole (1) (50 g, 0.164 mol) inglacial acetic acid (750 ml) while maintaining the temperature at 15° C.Acetic anhydride (250 ml) was added and the reaction mixture was stirredat room temperature for 2 hours. Once the reaction was complete, thereaction mixture was poured onto crushed ice (1 kg). After stirring for1 hour, the crude product was filtered off and then washed withdemineralized water (2×60 ml) to give crude1-nitro-3,4,5-tribromopyrazole. The water (24.6 ml) contained in the wetproduct was removed by heating a solution of the product in toluene (750ml) at reflux in Dean-Stark apparatus. The toluene solution wasmaintained at reflux for a further 30 minutes until a TLC (eluent:toluene) showed that the rearrangement of the1-nitro-3,4,5-tribromopyrazole (R_(f)=0.77), the intermediate formed,into 3,5-dibromo-4-nitropyrazole 2 (R_(f)=0.05) was complete. Thesolution was concentrated to a residual volume of 150 ml and then cooledto 60° C., followed by addition of hexane (275 ml). The solution wascooled to 0-5° C. for 1 hour and the 3,5-dibromo-4-nitropyrazole (2)(29.1 g, 65%) was recovered by filtration and drying under vacuum in theform of a pale yellow solid.

[0069] Melting point: 127.6-130.1° C.

[0070] Synthesis of 3,5-dibromo-1-ethyl-4-nitro-1H-pyrazole (3):

[0071] A mixture of 4-nitro-3,5-dibromopyrazole (2) (20.0 g; 73.8 mmol)in DMF (160 ml) was added over 20 minutes to a suspension of NaH (3.3 g,82.5 mmol; 60% dispersion in oil, prewashed with hexane) in DMF (160 ml)with stirring and under an inert atmosphere. After stirring for 30minutes, a solution of bromoethane (19.3 g; 177.1 mmol) in DMF (35 ml)was added over 5 minutes. The reaction mixture was heated to 70° C. for4 hours and the DMF was then evaporated off under reduced pressure (oilpump) while heating the reaction medium to 80° C. A DCM/water mixture(200 ml, 1/1) was added. The aqueous phase was washed with DCM (100 ml)and the combined organic phases were then washed with water (50 ml). Theorganic phase was dried over NaSO₄ and the solvent was evaporated offunder reduced pressure. The crude3,5-dibromo-1-ethyl-4-nitro-1H-pyrazole (19.6 g, 89%) is obtained in theform of a solid. This product is used without purification in thefollowing step.

[0072] Synthesis of (5-bromo-2-ethyl-4-nitro-2H-pyrazol-3-yl)ethylamine(4-1):

[0073] A mixture of 3,5-dibromo-1-ethyl-4-nitro-1H-pyrazole (28.4 g; 95mmol), EtOH (470 ml) and ethylamine (45.0 g, 700 mmol) was refluxed for3 hours. The reaction medium was concentrated to the maximum underreduced pressure (rotary evaporator, water bath at 40° C.). The brownoil obtained was suspended in DCM (250 ml) and water (250 ml). Theaqueous phase was washed with DCM (50 ml). The combined aqueous phaseswere extracted with DCM (50 ml) and the combined organic phases werethen dried over NaSO₄. After evaporating off the solvent, a solid wasobtained (24.6 g), which was purified by chromatography on silica gel(eluent: EtOAc/hexane) to give(5-bromo-2-ethyl-4-nitro-2H-pyrazol-3-yl)ethylamine (11.4 g, 45%) in theform of a yellow solid.

[0074] Melting point: 84.9-87.4° C.

[0075] Elemental analysis (C₇H₁₁N₄O₂Br)

[0076] Found: C, 31.92%; H, 4.05%; N, 21.14%; Br, 30.76%.

[0077] Theory: C, 31.96%; H, 4.21%; N, 21.30%; Br, 30.37%.

[0078]¹H-NMR (400 MHz, CDC1₃):

[0079] 4.18 (2H, q, J=7.3 Hz, NCH₂CH₂); 3.53 (2H, qd, J=7.2 Hz and 5.9Hz, NHCH₂CH₃), 1.46 (3H, t, J=7.3 Hz, NCH₂CH₃); 1,37 (3 h, t, J=7.2 Hz,NHCH₂CH₃).

[0080] Synthesis of1-(5-bromo-2-ethyl-4-nitro-2H-pyrazol-3-ylamino)propan-2-ol (4-2):

[0081] A mixture of 3,5-dibromo-1-ethyl-4-nitro-1H-pyrazole (3) (20.0 g;66.9 mmol), EtOH (100 ml) and 1-amino-2-propanol (25.1 g, 334.2 mmol)was refluxed for 15 hours. The reaction medium was concentrated to themaximum under reduced pressure and the excess 1-amino-2-propanol wasthen distilled off under vacuum. The oil obtained was suspended in DCM(100 ml) and water (100 ml). The aqueous phase was washed with DCM (100ml). The combined organic phases were washed with water (50 ml) and werethen dried over NaSO₄. After evaporating off the solvent under reducedpressure, a brown solid was obtained (19.1 g), which was purified bychromatography on silica gel (eluent: EtOAc/hexane). Afterrecrystallization of the solid from an EtOAc/hexane mixture (13 ml/20ml), the 1-(5-bromo-2-ethyl-4-nitro-2H-pyrazol-3-ylamino)propan-2-ol wasobtained in the form of a yellow solid (7.1 g, 36%).

[0082] Melting point: 82.7-84.2° C.

[0083] Elemental analysis (C₈H₁₃N₄O₃Br)

[0084] Found: C, 32.80%; H, 4.36%; N, 27.12%; Br, 18.86%.

[0085] Theory: C, 32.78%; H, 4.47%; N, 27.26%; Br, 19.11%.

[0086]¹H-NMR (400 MHz, CDCl₃):

[0087] 7.09 (1H, s, NH); 4.14 (2H, m, CH₂CH₃), 4.06 (1H, m, CH(OH)),3.47 (1H, m, CH₂NH), 3.31 (1H, m, CH₂NH), 1.59 (1H, s, OH), 1.46 (3H, t,J=7.3 Hz, CH₂CH₃), 1.30 (3H, d, CH(OH)CH₃).

[0088] Synthesis of 2,N3-diethyl-2H-pyrazole-3,4-diamine hydrobromide(5-1):

[0089] A mixture of1-(5-bromo-2-ethyl-4-nitro-2H-pyrazol-3-yl)ethylamine (4-1) (9.1 g; 35mmol) in EtOH (500 ml) containing 10% Pd/C as catalyst (Johnson-MatteyType 487, 2.0 g wet, 0.9 g dry weight) and hydrobromic acid (48%, 10.9g, 80 mmol) was hydrogenated in an autoclave (11) at 11 bar for 15hours. The catalyst was filtered off and washed with EtOH (50 ml), andthe filtrate was evaporated under reduced pressure. Acetone was addedunder an inert atmosphere and with stirring. After stirring for 20minutes, a white solid was obtained. After stirring for 1 hour, theprecipitate formed was recovered by filtration and was washed withacetone (100 ml) under an inert atmosphere and then dried under vacuum(over P₂O₅) to give the 2,N3-diethyl-2H-pyrazole-3,4-diamine in the formof the hydrobromide (1.77 HBr), as a white solid (7.5 g, 69%).

[0090] Melting point: 190.6-192.2° C.

[0091] Elemental analysis (C₇H₁₄N₄, 1.77 HBr):

[0092] Found: C, 31.42%; H, 5.34%; N, 15.31%; Br, 45.70%.

[0093] Theory: C, 28.27%; H, 5.34%; N, 18.83%; Br, 47.55%.

[0094]¹H-NMR (400 MHz, d⁶-DMSO):

[0095] 13.8 (2H, s, NH₂); 9.53 (1H, s, NH), 7.47 (1H, s, H_(Ar)), 3.98(2H, q, J=7.0 Hz, NH₂CH₃), 3.07 (2H, m, NHCH₂CH₃), 1.27 (3H, t, J 7.0Hz, NCH₂CH₃), 1.09 (3H, t, J=7.0 Hz, NHCH₂CH₃).

[0096] Synthesis of 1-(4-amino-2-ethyl-2H-pyrazol-3-ylamino)-propan-2-olhydrobromide (5-2):

[0097] A mixture of1-(5-bromo-2-ethyl-4-nitro-2H-pyrazol-3-ylamino)propan-2-ol (4-2) (7.0g; 23.9 mmol) in EtOH (500 ml) containing 10% Pd/C as catalyst(Johnson-Mattey Type 487, 1.6 g wet, 0.7 g dry weight) and hydrobromicacid (48%, 9.1 g, 54.0 mmol) was hydrogenated in a Parr autoclave (11)at 11 bar for 15 hours. The catalyst was removed by filtration andwashed with EtOH (50 ml), and the filtrate was evaporated under reducedpressure (rotary evaporator, 45° C. water bath) to give an orange-redoil (14.2 g). Under an inert atmosphere, the oil was dissolved in hotethanol (10 ml). After adding EtOAc (30 ml), the reaction mixture wascooled to 0-5° C. for 1 hour and a white precipitate formed. Afterfiltration and drying, the1-(4-amino-2-ethyl-2H-pyrazol-3-ylamino)propan-2-ol hydrobromide (1.92HBr) was obtained in the form of a white solid (5.6 g, 67%).

[0098] Melting point: 180.0-182.4° C.

[0099] Elemental analysis (CBH_(17.92)N₄OBr_(1.92)):

[0100] Found: C, 27.30%; H, 5.08%; N, 15.51%; Br, 47.35%.

[0101] Theory: C, 27.77%; H, 5.24%; N, 16.19%; Br, 46.18%.

[0102]¹H-NMR (400 MHz, d⁶-DMSO):

[0103] 9.59 (1H, S_(broad), NH), 7.36 (1H, S, H_(Ar)), 3.97 (2H, q,J=7.3 Hz, NCH₂CH₃), 3.75 (1H, m, CH(OH)), 3.06 (1H, m, CH(OH)), 2.93(2H, m, NHCH₂CH(OH)), 1.26 (3H, t, J=7.3 Hz, NCH₂CH₃), 1.11 (3H, d, J6.6 Hz, CH(OH)CH₃).

EXAMPLES OF DYEING IN ALKALINE MEDIUM

[0104] The dye formulations below are prepared: 4,5-diaminopyrazole offormula (I) 5 × 10⁻³ mol coupler 5 × 10⁻³ mol oleyl alcoholpolyglycerolated with 4.0 g 2 mol of glycerol oleyl alcoholpolyglycerolated with 5.7 g A.M. 4 mol of glycerol, containing 78%active material (A.M.) oleic acid 3.0 g oleylamine containing 2 mol ofethylene 7.0 g oxide, sold under the trade name Ethomeen O12 by thecompany Akzo diethylaminopropyl laurylamino succinamate, 3.0 g A.M.sodium salt, at 55% A.M. oleyl alcohol 5.0 g oleic acid diethanolamide12.0 g propylene glycol 3.5 g ethyl alcohol 7.0 g dipropylene glycol 0.5g propylene glycol monomethyl ether 9.0 g sodium metabisulfite as anaqueous 0.455 g A.M. solution containing 35% A.M. ammonium acetate 0.8 gantioxidant, sequestering agent qs fragrance, preserving agent qsaqueous ammonia containing 20% NH₃ 100 g

[0105] The pH of the composition is 9.5

[0106] A.M. means “active material” Examples Base Coupler 12,N3-diethyl-2H-pyrazole- 5-amino-6-chloro-2- 3,4-diamine, 1.77 HBr(5-1) methylphenol 2 2,N3-diethyl-2H-pyrazole- 2-methyl-5- 3,4-diamine,1.77 HBr (5-1) aminophenol 3 2,N3-diethyl-2H-pyrazole-1-β-hydroxyethoxy- 3,4-diamine, 1.77 HBr (5-1) 2,4-diaminobenzene, 2HCl4 1-(4-amino-2-ethyl-2H- 5-amino-6-chloro-2- pyrazol-3-ylamino)propan-2-methylphenol ol, 1.92 HBr (5-2) 5 1-(4-amino-2-ethyl-2H- 2-methyl-5-pyrazol-3-ylamino)propan-2- aminophenol ol, 1.92 HBr (5-2) 61-(4-amino-2-ethyl-2H- 1-β-hydroxyethoxy- pyrazol-3-ylamino)propan-2-2,4-diaminobenzene, ol, 1.92 HBr (5-2) 2HCl

[0107] At the time of use, each dye composition is mixed, weight forweight, with a 20-volumes aqueous hydrogen peroxide solution (6% byweight), the pH of which has been adjusted to about 2.5 withorthophosphoric acid.

[0108] The mixture is applied to natural or permanent-waved grey haircontaining 90% white hairs, at a rate of 5 g per 0.5 g of hair, for 30minutes.

[0109] The hair is then rinsed, washed with a standard shampoo anddried.

[0110] The color of the locks was evaluated in the L*a*b* system, onwhite and permanent-waved hair, using a Minolta CM 2002spectrophotometer.

[0111] In the L*a*b* space, the lightness is indicated by the value L*on a scale from 0 to 100, while the chromatic data is expressed by a*and b* which indicate two color axes, a* the red-green axis and b* theyellow-blue axis.

[0112] According to this system, the higher the value of L, the palerand less intense the color. Conversely, the lower the value of L, thedarker or more intense the color. Natural white hair Permanent-wavedwhite hair Example L* a* b* L* a* b* Example 1 35.5 29.8 −1.34 28.2 30.6−0.07 Example 2 42.2 26.6 7.97 34.7 30.5 8.02 Example 3 30.0 12.0 −8.6822.2 10.5 −7.5 Example 4 40.7 27.4 1.12 30.7 30.7 1.01 Example 5 43.627.0 9.32 33.0 31.7 11.3 Example 6 33.3 12.8 −6.7 22.8 11.9 −7.11

[0113] The 4,5-diaminopyrazoles according to the invention thus make itpossible to obtain strong and chromatic shades at alkaline pH.

1. A diaminopyrazole compound of formula (I):

in which: R₁ and R₂, which may be identical or different, denote aethyl, n-propyl, isopropyl or mono- or polyhydroxy (C₃-C₅)alkyl group,it being possible for these groups to be linear or branched, and thephysiologically acceptable salts thereof.
 2. The compound of formula (I)as claimed in claim 1, characterized in that the physiologicallyacceptable salts are acid salts chosen from the hydrochlorides,hydrobromides, sulfates, tartrates, lactates and acetates.
 3. Thecompound of formula (I) as claimed in claim 1 or 2, characterized inthat R1 denotes a linear or branched ethyl, n-propyl, isopropyl, propyl,butyl or pentyl group, which is substituted with one or more OHradicals.
 4. The compound of formula (I) as claimed in any one of claims1 to 3, characterized in that R2 preferably denotes an ethyl, n-propyl,isopropyl, ethyl, propyl, butyl or pentyl group, which is substitutedwith one or more OH, it being possible for these groups to be linear orbranched.
 5. The compound of formula (I) as claimed in any one of claims1 to 4, characterized in that it is2,N3-diethyl-2H-pyrazole-3,4-diamine,1-(4-amino-2-ethyl-2H-pyrazol-3-ylamino)propan-2-ol or one of thephysiologically acceptable salts thereof.
 6. A composition for theoxidation dyeing of keratin fibers, and in particular of human keratinfibers such as the hair, characterized in that it contains, in a mediumthat is suitable for dyeing, as oxidation base, at least onediaminopyrazole of formula (I):

in which: R₁ and R₂, which may be identical or different, denote aethyl, n-propyl, isopropyl or mono- or polyhydroxy(C₃-C₅)alkyl group, itbeing possible for these groups to be linear or branched, and thephysiologically acceptable salts thereof.
 7. The composition as claimedin claim 6, characterized in that it contains from 0.001% to 10% byweight of at least one diaminopyrazole of formula (I) or salt thereof.8. The composition as claimed in claim 7, characterized in that itcontains from 0.05% to 6% by weight and preferably 0.1% to 3% by weightof at least one diaminopyrazole of formula (I) or salts thereof.
 9. Thecomposition as claimed in any one of claims 6 to 8, characterized inthat the medium that is suitable for dyeing consists of water or of amixture of water and at least one organic solvent chosen from C₁-C₄lower alkanols, polyols and polyol ethers, aromatic alcohols andmixtures thereof.
 10. The composition as claimed in any one of claims 6to 9, characterized in that it has a pH of between 3 and
 12. 11. Thecomposition as claimed in any one of claims 6 to 10, characterized inthat it contains at least one additional oxidation base chosen frompara-phenylenediamines, bis(phenyl)alkylenediamines, para-aminophenols,ortho-aminophenols and heterocyclic bases other than the substitutedN3-diaminopyrazole of formula (I), and addition acid salts thereof. 12.The composition as claimed in claim 11, characterized in that theadditional oxidation base(s) represent(s) from 0.0005% to 12% by weightrelative to the total weight of the dye composition.
 13. The compositionas claimed in any one of claims 6 to 12, characterized in that itcontains at least one coupler and/or at least one direct dye.
 14. Thecomposition as claimed in claim 13, characterized in that the coupler(s)is (are) chosen from meta-phenylenediamines, meta-aminophenols,meta-diphenols, mono- or polyhydroxylated naphthalene derivatives andheterocyclic couplers, and the addition acid salts thereof.
 15. Thecomposition as claimed in either of claims 13 and 14, characterized inthat the coupler(s) represent(s) from 0.0001% to 10% by weight relativeto the total weight of the dye composition.
 16. The composition asclaimed in any one of claims 6 to 15, characterized in that the additionacid salts are chosen from the hydrochlorides, hydrobromides, sulfates,tartrates, lactates and acetates.
 17. A process for dyeing keratinfibers, and in particular human keratin fibers such as the hair,characterized in that at least one dye composition as defined in any oneof claims 6 to 16 is applied to these fibers, for a time that issufficient to develop the desired coloration, either in air or using anoxidizing agent, optionally in the presence of oxidation catalysts. 18.The process as claimed in claim 17, characterized in that the colorationis revealed solely on contact with atmospheric oxygen.
 19. The processas claimed in claim 17, characterized in that the color is revealed atacidic, neutral or alkaline pH with the aid of an oxidizing agent, whichis added to the dye composition just at the time of use, or which ispresent in an oxidizing composition applied simultaneously orsequentially in a separate manner.
 20. The process as claimed in claim17 or 19, characterized in that the oxidizing agent is chosen fromhydrogen peroxide, urea peroxide, alkali metal bromates and persaltssuch as perborates and persulfates.
 21. A multi-compartment device ormulti-compartment dyeing “kit”, a first compartment of which contains adye composition as defined in any one of claims 6 to 16, and a secondcompartment of which contains an oxidizing composition.